Thomas Edison`s Universal Stock Ticker is perhaps the single most iconic piece of Wall Street technology. But, Thomas Edison was not the ticker`s original inventor. That distinction goes to Edward Calahan of the American Telegraph Company, who invented the ticker in 1867. The original stock ticker looked similar to Edison`s model, but with a major distinction. Calahan`s model had one large wheel that printed both letters and numbers. Edison—always eager to improve on other people`s inventions—realized he could increase the ticker`s speed by adding a second wheel. With two small wheels spinning simultaneously—one for letters and one for numbers—its speed nearly doubled. Edison`s ticker hit the market in 1871 and quickly became the industry standard. Edison`s ticker is perhaps most famous—and infamous—for its use during the Stock Market Crash of 1929. On Black Tuesday, October 29, stock tickers couldn't keep up with the increased trading volume as Wall Street panicked. The information coming out of the tickers lagged behind the actual transactions happening at the New York Stock Exchange by several hours. Not having accurate stock prices made most investors and brokers very anxious, which exaggerated the sense of panic. One of the few good things that came out of the Crash of `29 was a redesigned ticker in the early 1930s. Between the 1930s and the 1960s, several new models appeared on the market, but then the electronic age quickly rendered mechanical tickers obsolete.